Stabilized yeasted milk suspension and method of making the same



Patented Mar. 19, 1935 1,994,496

STABILIZED YEASTED MILK SUSPENSION AND METHOD OFMAKING THE SAME Louis Warncke, Weehawken, 'N. J., assignor to Charles L. Patterson No Drawing. Application December 21, 1931,

. Serial No. 582,497

15 Claims. (01. 99-113 My present invention is concerned with. the ing a recognized nutritive value of its own yet provision of a modified milk beverage and a substantially tasteless in the suspension and not method of manufacturing it. It finds its prenoticeably affecting the consistency of the susferred embodiment in a process for manufacturpension. i ing yeasted milk and the product of such process. Another more specific object is to provide a 5 More specifically, the present invention reprehomogenized sweet milk containing live yeast in sents an improvement in the process and product suspension, and containing gelatin as a suspendescribed in my copending application Serial No. sion stabilizer and retaining the full nutritive and 450,315, filed May 6, 1930. medicinal value of all three of these substances.

An object of the invention is to produce a In accordance with a preferred embodiment l0 highly palatable modified milk beverage containof the method, I take a batch of any kind of ing substantially pure yeast and to thereby elimisweet raw milk, that is to say, milk including all nate the present necessity for consuming the of the fatty and albuminous content, and pasyeast cake in a highly unpalatable form and in teurize it by heating it to a temperature of above a form 'in which the consumer who is eating the 143 degrees F., and holding it at this heat for 15 yeast for medicinal purposes is obliged to conat least a half hour as called for by the board sume a considerable quantity of starchwhich of health regulations. This heat, maintained may in some cases ofiset, at least in part,'the over the specified period, destroys dangerous medicinal value of the yeast itself. pathogenic organisms.

Another object is to provide a yeasted milk While this batch is at the pasteurizing temper- 20 which will fully meet the requirements of the ature or is just starting to cool down below the board of healthregulations as to pasteurization, pasteurizing temperature I preferably introduce and yet which will contain the essential vitamins a small batch of pre-pasteurized milk contain- A, 131, D and G (the latter being the antiing the proper amount of gelatin dissolved therepellagric vitamin which can be autoclaved and in. If desired, the gelatin maybe dissolved in 25 which is also known as B2). unpasteurized milk and introduced into the Another object of the invention is to provide batch at. the pasteurizing temperature. Prefera yeasted milk of the highly nutritive and meablythe gelatin added is about .6% of the total dicinal character set forth above in which all batch of milk and in a typical batch of eleven of the nutritive values of the yeast and milk are quarts of milk two quarts may be used to dis- 0 combined and the characteristics of both yeast solve the gelatin. and milk which tend to render both substances The purpose of the gelatin which is recognized unpalatable to certain people are substantially as a stabilizer of emulsions, is to produce in the neutralized and offset one by the other, the represent instance a stabilized suspension having sulting beverage containing none of the chalky colloidal characteristics, particularly at lowtem- 35 taste which characterizes skimmed milk and the peratures which will prevent the yeast cells or sugar and fatty content of the milk almost comparticles from settling out. pletely disguising the taste of the yeast so that The pasteurized gelatinized milk is then cooled the beverage has a sweet creamy taste with a rapidly down-to at least 120 degrees F. preferi 40 faint yeast flavor. ably to about 116 degrees and liquid yeast is 40 Another object of the invention is to provide a added to the batch. The amount of yeast added method of making the beverage which may be may vary considerably since it is entirely poscarried out with expedition and facility and sible to make a very concentrated yeasted milk which will avoid the necessity for utilizing a solution, but inasmuch as the usualmedical regreater number of heating and cooling steps than quirement for patients requiring yeast is about those employed in the usual pasteurizing process. three cakes a day, I prefer to add about one and Another object is to provide a yeasted milk in one-half ounces of yeast for each quart of gelawhich the yeast cells will not settle out and detinized milk in the batch or roughly one pound posit in the bottom of the bottle even though to a batch of eleven quarts of milk. This amount the milk has stood for a long period of time, and is equivalent to about three cakes of'the ordinary even though the milk has been subjected to yeast per quart of milk but is less by volume than widely varying temperatures. the three cakes, due to the fact that I employ Another object is to provide a beverage of yeast which is substantially devoid of starch. this character containing in addition to the Preferably the yeast which is to be added is yeasted milk, a suspension stabilizing agent havfirst dissolved in prepasteurized milk at a temperature of about degrees F., and in the quantity of one pound of yeast to one quart of milk.

This dissolving action is merely intended to facilitate the complete and thorough mixture of the yeast with the batch of gelatinized milk, and it is, of course, within the scope of the invention to introduce active or viable yeast directly into the partially cooled milk containing the gelatin.

is introduced therein may run at least as high" as degrees F. and at least as low as 100 degrees F. I do not intend to limit myself definitely to these temperature ranges but they have been found most effective in practice. A temperature of about 116 degrees F. is preferred. If the yeast is introduced at a temperature much above 120 degrees, many of the yeast cells are killed, being unable to withstand the heat, and if the yeast is introduced when the milk is much below 100 degrees or below body temperature, the fat in the milk is diflicult to emulsify.

Having added the yeast to the batch the latter is then cooled toapproximately'lOO degrees F. (thus guarding against destruction of any yeast germs) and immediately run through a homogenizer, emulsifier, viscolizer, colloid mill, high pressure pump or under a pressure of preferably about 2000 pounds per square inch, this pressure of course being subject to variation in accordance with the amount of yeast contained in the milk and with the characteristics of the milk itself.

The homogenizer, which may be of conventional type, in which a fine stream of milk under high pressure is squirted against a baflle plate, apparently serves a triple function in the present process. In the first place, it completely breaks down the fatty or albuminous globules in the milk and forms a complete emulsion to prevent subsequent stratification by gravity of the milk contents so that no cream will rise' to the surface even though the emulsion be kept in an ice box or even subjected to widely varying temperatures for several days. Secondly the emulsifying under pressure increases the viscosity of the milk. The third function apparently performed by the homogenizer is to break up the yeast into individual cells or small cell groups thereby pro ducing a yeast suspension.

There is not sufiicient information available on the subject of the yeast cell to enable me to unqualifiedly state just what occurs in the homogenizing operation or to state exactly how (disregarding the gelatin) a yeast suspension is produced. I may advance the tentative theory that the yeast which is a egetable-like growth of linked or stringy cellular construction has its cells broken up and separated in the homogenizer and that these cells may have a tendency to cling to the fatty. particles which are in suspension or in emulsion in the milk.

With gelatin added-and with the homogenizing mixture cooled down to ice box temperatures say about 55 I find that the live yeast cells apparently remain in a substantially dormant condition, the yeast content showing no tendency to increase materially. The gelatin which forms by homogenizing the fat, casein and gelatin particles) cohere.

'mately the nutritive amount, of, gelatin suspension by the yeast of Submicroscopic particles of gelatin occlude large amounts of water, whereby the'relativ'e volume The temperature of the batch when the yeast occupied by the gelatin is increased. These microscopic particles are the beginning of a continuous gel, to which the gelatin solution has a tendency to set. a

There is apparently a colloidal structure built up in the emulsion which has varying degrees of stability dependent upon concentration, temperature and time. Freedom of motion is lost at the setting point and the adjacent aggregates (yeast, Milk allowed to stand for a time at low temperatures becomes more viscous. Homogenized milk has a still greater viscosity. During the aging of the emulsion such as that described herein, I assume that the increase in viscosity is due to absorption of the casein and other colloids'by the fat. With an increase in theamount of fat or the division of the fat globules by homogenization, there is a corresponding increase in the surface area to which colloids may be absorbed, the fat being in the form of.,globules the size of which determines to a large extent the amount of colloids absorbed.

There is some evidence to indicate that the addition of the small amount of gelatin also increases the specific gravity of the homogenized milk to a point where it is substantially identical with the specific gravity of the yeast cells. This increase in specific gravity is very slight but it apparently aids to some extent at least in retarding or'preventing the settling out of the yeast at room temperatures. 1

In practicing the method, the milk afterhomogenization is cooled with sufficient rapidity to take advantage of desirable stabilizing property of the gelatin before any settling out of yeast can occur, even where the specific gravity of the yeast cells and the homogenized gelatinized milk are not identical. A quart of milk formed in accordance with the disclosure of this application contains approxivalue of a quart. of pasteurnutritive' value of a slight and plus aboutthree cakes without the starch which is commonly used in such cakes. By yeasting the milk the valuable vitamins B1, D and B2 are added to the vitamins A and B1 and sometimes D contained in the milk and a highly nutritive and palatable beverage is obtained in which the B1, B2 and D vitamins predominate.

By practicing the tirely unforeseen result is obtained insofaras the palatability of the final product isconcerned.

An ounce and a in ordinary milk gives the milk a. very decided yeasty flavor, and a beverage thus produced'is only slightly less palatable than a dry yeast cake. The homogenizing .process which I utilize, however, seems to so thoroughly mix the yeast with the creamy and sugary content of the milk that the resultant beverage is highly palatable. It has a very faint yeasty taste and it does not have either the greasy and somewhat sickening taste of cream nor does it have the chalky taste of skimmed milk. The beverage, which has little more viscosity than ordinary mill: and which is ized milk plus the of ordinary yeast process as described, an en--,

half of yeast simply dissolved in fact less viscous than cream, has a somewhat sweet and not unpleasant creamy taste with a very faint tang of yeast. Apparently, the natural flavors of the yeast and the milk counteract each other to a large extent, with a resultant product which is more palatable than either of them alone. 1

While I have discussed the palatability of the beverage formed exactly in accordance with my process, it will be understood of course that it is within the scope of the invention to dissolve any desirable flavoring material, such for instance as chocolate, in the beverage, in which instance the presence of yeast will be hard to detect by tasting the beverage.

While the product is primarily intended for beverage purposes, one of its advantages is that it can be used for cooking and when so used the product cooked with the milk, or the milk or cream sauce on the product, has no flavor of yeast whatsoever. This is due to the fact that the usual cooking temperatures are well above 120 so that all of the yeast cells are killed and the aroma of the yeast is killed with them.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:-

I. As a new foodstuff, a suspension consisting of homogenized sweet milk and yeast and less than 1% of a stabilizing agent.

2. As a new foodstuff, a suspension consisting of homogenized sweet milk and yeast and less than 1% of a colloidal -stabilizing agent highly viscous at low temperatures.

3. As a new foodstufl', a beverage consisting of pasteurized, homogenized, raw, sweet milk and yeast and a small amount of gelatin.

4. As a new foodstuff, homogenized, pasteurized, raw, sweet milk including a small proportion of live but dormant liquid yeast and a smaller proportion of a colloidal suspension stabilizing agent.

5. As a new foodstuff, homogenized, pasteurized, raw, sweet milk including a small proportion of live but dormant liquid yeast and a smaller proportion of a suspension stabilizing agent, said agent comprising gelatin in proportions of less than 1% of the batch.

6. As a new foodstufi, homogenized, pasteurized, raw, sweet milk including a small proportion of yeast distributed substantially uniformly throughout the milk and a lesser proportion of gelatin stabilizing the yeast suspension.

7. A method of producing a stabilized suspension of yeast in milk which includes the steps of introducing yeast and gelatin into the milk and homogenizing the mixture thus formed. 8. A method of producing a stabilized suspension of yeast in milk which includes the steps of introducing yeast and gelatin into the milk and homogenizing the mixture thus formed, the homogenization being effected under a pressure in the order of two thousand pounds per square inch.

9. A method of forming a stabilized suspension of yeasted milk which includes the steps of subjecting the milk to a pasteurizing temperature of about 143 F., adding a small amount of gelatin to the milk, cooling the milk to about 116 F., introducing a small amount of liquid yeast into the milk at a temperature of 116 F. and 100 F. and running the mixture thus formed through a homogenizer under high pressure.

10. A method as set forth in claim 9 wherein the gelatin comprises approximately .6% of the batch.

11. The method as set forth in claim 9 wherein the homogenized mixture is rapidly cooled to a temperature where the yeast cells are substantially dormant.

12. A method as set forth in claim 9 wherein the mixture is run through the homogenizer at a pressure of about two thousand pounds per square inch.

13. A method of rendering more palatable and forming a stable suspension of raw milk containing yeast which includes the steps of adding gelatin and running the mixture through a homogenizer at high pressure.

14. As a new foodstuff, a suspension consisting of homogenized sweet milk and yeast and a colloidal stabilizing agent of greater viscosity than the milk whereby to deter settling out of the yeast from the suspension.

15. As a new foodstuff, milk rendered more viscous by homogenization and containing yeast in suspension together with a small amount of stabilizing agent of greater viscosity than the homogenized milk. 1

LOUIS WARNCKE. 

